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"Innovative firearm accessories engineered for performance"

SI designs rugged, user-focused firearm components and optics. They make accessories like slide plates, charging handles, barrel clamps, red dots, and shotgun parts.

5.0★★★★★(82 verified SI reviews)

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7,593

Products

2,364

In Stock

Founded

USA

Origin

All SI Products (2,364)

Sinclair INTERNATIONAL LARGE CALIBER NECK TURNING MANDREL SS 50 CALIBER

Sinclair INTERNATIONAL LARGE CALIBER STAINLESS EXPANDER MANDREL 50 CALIBER

Sinclair INTERNATIONAL TRIMMER SPACER

Sinclair INTERNATIONAL LARGE CALIBER NECK TURNING MANDREL SS 416 CALIBER

Sinclair INTERNATIONAL LARGE CALIBER NECK TURNING MANDREL SS 9.3MM (.364")

Sinclair INTERNATIONAL LARGE CALIBER NECK TURNING MANDREL SS 35 CALIBER

Sinclair INTERNATIONAL LARGE CALIBER STAINLESS EXPANDER MANDREL 416

Sinclair INTERNATIONAL LARGE CALIBER STAINLESS EXPANDER MANDREL 375

Sinclair INTERNATIONAL LARGE CALIBER STAINLESS EXPANDER MANDREL 9.3MM (.365")

Sinclair INTERNATIONAL REPLACEMENT NECK TURNING CUTTER 40 DEGREE

Sinclair INTERNATIONAL REPLACEMENT NECK TURNING CUTTER 30 DEGREE

Sinclair INTERNATIONAL BIPOD ADAPTER STANDARD RAIL

Sinclair INTERNATIONAL FLASH HOLE TOOL ONLY

Sinclair INTERNATIONAL NECK TURNING MANDREL SS 20 CALIBER (.202")

Sinclair INTERNATIONAL STAINLESS STEEL EXPANDER MANDREL 20 CALIBER (.203")

Sinclair INTERNATIONAL NECK TURNING MANDREL SS 270 CALIBER (.275")

Sinclair INTERNATIONAL NECK TURNING MANDREL SS 25 CALIBER (.255")

Sinclair INTERNATIONAL STAINLESS STEEL EXPANDER MANDREL 25 CALIBER (.256")

Sinclair INTERNATIONAL STAINLESS STEEL EXPANDER MANDREL 338 CALIBER (.337")

Sinclair INTERNATIONAL NECK TURNING MANDREL SS 17 CALIBER (.170")

Sinclair INTERNATIONAL STAINLESS STEEL EXPANDER MANDREL 17 CALIBER (.171")

Sinclair INTERNATIONAL BRENCHREST PRACTICE TARGETS 25 PACK

Sinclair INTERNATIONAL RPM BENCH MAT 16"X20"

Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 30 CALIBER

Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 7MM

Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 6.5MM

Sinclair International Pilot Stop Stainless Steel 6mm

Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 25 CALIBER

Sinclair International Pilot Stop Stainless Steel .45 Caliber

Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 270 CALIBER

Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 35 CALIBER

Sinclair INTERNATIONAL PILOT STOP STAINLESS STEEL 375 CALIBER

Sinclair INTERNATIONAL BULLET SEATING DEPTH GUIDE 0.690" DIAMETER

Sinclair International Priming Tool Shell Holder #19 9mm/40 S&W/10mm

Sinclair INTERNATIONAL ROD GUIDE INSERT 22 CALIBER

Sinclair INTERNATIONAL CLEANING ROD WALL BRACKET

Sinclair International Bore Brush 44/45 8-32M

Sinclair Nylon Rifle Bore Brush 30 Caliber 12 Pack

Sinclair International Bore Brush 204 Ruger

Sinclair INTERNATIONAL NYLON RIFLE BORE BRUSH 17 CALIBER 8-32M 12 PACK

Sinclair International Pistol Brush 44/45

Sinclair International Bronze Pistol Brush 10mm

Sinclair International Bronze Pistol Brush 9mm

Sinclair International Bronze Pistol Brush

Sinclair International Pistol Brush 17 Caliber

Sinclair International Bronze Brush 50 BMG 8-32M

Sinclair INTERNATIONAL BRONZE RIFLE BORE BRUSH 41 CALIBER 8-32M 12 PACK

Sinclair International Bore Brush 375 Caliber

About SI

SI focuses on practical, performance-driven firearm accessories for a wide range of pistols, rifles, and shotguns. Their lineup includes slide adapter plates, latchless charging handles, barrel clamps, compact red dot optics, and dedicated shotgun components, built primarily from aluminum and hardened materials. Products are engineered with attention to fit, function, and ease of installation, aimed at shooters who want reliable upgrades without unnecessary complexity. SI supports competitive, tactical, and recreational shooters by offering parts that address common user needs and enhance firearm ergonomics and capability.

Headquarters

Established

Country of Origin

USA

History & Heritage

SI began as an American aftermarket parts maker aimed at providing functional, affordable upgrades and accessories for shooters. Over time the brand expanded its offerings across pistol, rifle, and shotgun platforms, becoming known for practical designs and broad compatibility.